A new steady-state traffic noise model for estimating L(h) on free flow roads using Reference Energy Mean Emission Levels

2021 ◽  
pp. 107685
Author(s):  
Sh Afandizadeh ◽  
H. Gharehdaghli
Keyword(s):  
Steady State ◽  
Traffic Noise ◽  
Free Flow ◽  
Noise Model

Calibration 7" – Cutthroat Flume as New Size for Discharge Measurement at Free Flow Condition

2020 ◽  
Vol 38 (12A) ◽  
pp. 1783-1789
Author(s):  
Jaafar S. Matooq ◽  
Muna J. Ibraheem
Keyword(s):  
Steady State ◽  
Flow Condition ◽  
Laboratory Experiments ◽  
Free Flow ◽  
Experimental Program ◽  
Steady State Flow ◽  
Empirical Formulas ◽  
State Flow ◽  
Operation Conditions ◽  
Throat Width

 This paper aims to conduct a series of laboratory experiments in case of steady-state flow for the new size 7 ̋ throat width (not presented before) of the cutthroat flume. For this size, five different lengths were adopted 0.535, 0.46, 0.40, 0.325 and 0.27m these lengths were adopted based on the limitations of the available flume. The experimental program has been followed to investigate the hydraulic characteristic and introducing the calibrated formula for free flow application within the discharge ranged between 0.006 and 0.025 m3/s. The calibration result showed that, under suitable operation conditions, the suggested empirical formulas can accurately predict the values of discharge within an error ± 3%.

Acoustic Modeling of Meteorological Effects on Roadway Noise

2021 ◽  
pp. 036119812199458
Author(s):  
Roger L. Wayson ◽  
Kenneth Kaliski
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Model Development ◽  
The United States ◽  
Noise Model ◽  
Road Traffic Noise ◽  
Atmospheric Conditions ◽  
Noise Propagation ◽  
Transportation Research ◽  
Meteorological Effects

Modeling road traffic noise levels without including the effects of meteorology may lead to substantial errors. In the United States, the required model is the Traffic Noise Model which does not include meteorology effects caused by refraction. In response, the Transportation Research Board sponsored NCHRP 25-52, Meteorological Effects on Roadway Noise, to collect highway noise data under different meteorological conditions, document the meteorological effects on roadway noise propagation under different atmospheric conditions, develop best practices, and provide guidance on how to: (a) quantify meteorological effects on roadway noise propagation; and (b) explain those effects to the public. The completed project at 16 barrier and no-barrier measurement positions adjacent to Interstate 17 (I-17) in Phoenix, Arizona provided the database which has enabled substantial developments in modeling. This report provides more recent information on the model development that can be directly applied by the noise analyst to include meteorological effects from simple look-up tables to more precise use of statistical equations.

Traffic Noise Model vs. Extreme Topography

2003 ◽  
Vol 1859 (1) ◽  
pp. 65-71
Author(s):  
Michael A. Staiano
Keyword(s):  
Traffic Noise ◽  
Severe Case ◽  
Sound Attenuation ◽  
Noise Model ◽  
Interstate Highway ◽  
Site Model ◽  
Sound Levels

Traffic noise exposures were measured at various locations adjacent to an Interstate highway and compared with sound levels predicted by the FHWA Traffic Noise Model (TNM). The prediction procedure underestimated the measured sound attenuation by 6 to 12 A-weighted decibels. Various TNM site model configurations were evaluated in an effort to improve agreement between measurements and predictions. For the site tested—a severe case with relatively distant receptors and extreme topography—variations in ground impedance (including a median ground zone) had little benefit or were counterproductive, while adding topographic detail via terrain lines helped somewhat. The best agreement resulted from the incorporation of a tree zone for the wooded site. However, this benefit is thought to be chance, because the site was not only relatively lightly wooded but also thinly foliaged at the time of the on-site measurements.

Comparison of Traffic Noise Model 2.5 with 2.1 and Measured Data

2005 ◽  
Vol 1941 (1) ◽  
pp. 149-154
Author(s):  
A. A. El-Aassar ◽  
R. L. Wayson ◽  
J. M. MacDonald
Keyword(s):  
Traffic Noise ◽  
Measured Data ◽  
Noise Model ◽  
Average Error ◽  
Matched Pairs ◽  
Federally Funded ◽  
Reference Measurement ◽  
Previous Version ◽  
Ground Effects ◽  
Predicted Values

Traffic Noise Model Version 2.5 (TNM 2.5) will soon be the official traffic noise model required by the FHWA for federally funded projects. TNM was updated from Version 2.1 to 2.5 to address two major issues: the overprediction found in the previous version of TNM and an anomaly related to diffraction points. This research focused on comparing the TNM 2.5 predicted results with TNM 2.1 predicted values and with measured data from 18 barrier locations in Florida. Matched pairs of predicted and measured differences between the data for TNM 2.5 and TNM 2.1 were evaluated and a direct comparison of the two models was made. This research demonstrated that the predicted results from TNM 2.5 had an average error for all 18 barrier locations of less than 1 dB. However, when each of the sites is evaluated individually, TNM 2.5 has a tendency to underpredict slightly at many of the evaluated barrier locations. Finally, TNM 2.5-predicted results tend to be about 3 dB(A) on average less than TNM 2.1 at a defined reference measurement position, which is relatively unaffected by ground effects or diffraction, and about 1 dB less at microphone positions behind evaluated barriers when compared with TNM 2.1.

Simulation Approach to Traffic Noise Modeling: American Automobile Manufacturers Association Community Noise Model Version 4.0

1997 ◽  
Vol 1601 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Roger L. Wayson ◽  
John M. MacDonald ◽  
Ronald Eaglin ◽  
Barbara Wendling
Keyword(s):  
Simulation Model ◽  
Traffic Noise ◽  
The United States ◽  
Point Sources ◽  
Noise Model ◽  
Community Noise ◽  
Model Free ◽  
Sound Levels ◽  
Acceleration And Deceleration ◽  
Interrupted Flow

Several models are available for predicting traffic noise levels. The FHWA-promulgated model, STAMINA 2.0, is the most widely used noise model in the United States and is used to model free-flow vehicular traffic. STAMINA 2.0 cannot directly model interrupted-flow traffic. Sound levels from interrupted-flow traffic can be approximated with STAMINA 2.0 using the method presented in NCHRP Report 311. This method is time-consuming and difficult to use. These limitations demonstrate the need for a traffic noise model that can model the acceleration and deceleration behavior of interrupted-flow traffic. The University of Central Florida has developed the American Automobile Manufacturers Association Community Noise Model (CNM). The CNM is a traffic simulation model that determines sound levels at receivers by modeling vehicles as discrete moving point sources. The vehicle energy is determined from acceleration, deceleration, idle, and cruise reference energy mean emission level curves. Sound energy attenuation is calculated from distance, ground absorption, and user input barriers. The model sums the energy at receivers from all vehicles and then calculates the Leq noise level at the receivers. It is demonstrated that the CNM predicts receiver Leq levels that are very close to STAMINA 2.0 results for constant-speed traffic. The CNM can also accurately predict sound levels at receivers located before and after intersections. In addition to the advantages of a real simulation model, the CNM is user friendly, allowing the user to place lanes and receivers using the mouse.

Creation of Theoretical Road Traffic Noise Model with the Help of GIS

2017 ◽  
Author(s):  
Kinga Szopinska
Keyword(s):  
Urban Space ◽  
Road Traffic ◽  
Traffic Noise ◽  
Noise Model ◽  
Road Traffic Noise ◽  
The European Union ◽  
Noise Emission ◽  
Starting Point ◽  
Information Layer ◽  
Gis Data

Road traffic noise, as a form of environmental pollution, is an important element causing discomfort among inhabitants and leading to the emergence of noise nuisance influencing the shaping of urban space. The basic tool in combating noise is a Strategic Noise Map (SNM), which, understood as a system, constitutes an element of a city’s information layer. The system, illustrating the noise situation within a city, is prepared by means of a calculationmeasurement method using specialized computer programs. The assessment of road traffic noise begins by defining the amount of noise emissions coming from acoustically-homogenous sections (emission map), and ends with determining the extent of noise propagation in urban space (immission map). The above process is based on the analysis of actual input data describing, in a detailed manner, the analyzed road infrastructure in terms of the characteristics of the road section, information on the volume and type of traffic, and data on the organization of traffic. Under such extensive analysis of the condition of the environment, it is appropriate to apply GIS data as a methodological basis for creating SNMs. GIS data make it possible to unify the rules for collecting and archiving values characterizing the condition of the environment, as well as parameters influencing the level of noise. The aim of work is create a theoretical road traffic noise model with the help of GIS. The scope of information in attribute tables of acoustically-homogenous road sections comprising a GIS thematic layer was described in detail. The above information are the basis for generating digital road traffic noise emission maps as well as being the starting point for assessing road traffic noise in the area of a city in the form of immission maps. The article additionally analyzes the results of data derived from the first phase of noise mapping in Europe, as well as familiarizing the reader with the procedure of modelling road traffic noise emission in accordance with the CNOSSOS-EU which will become binding as of 31 December 2018 throughout the European Union, and which was introduced by the provisions of the new noise directive – Directive 2015/996 of 19 May 2015.

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